Memory devices are integrated circuits in which information may be stored and from which information may be extracted when desired. Each memory device is built from a plurality of memory cells. Each memory cell memorizes a bit of data. Although a bit of data seems insignificant, it may determine whether the stored information is correct, such as an amount in a checking account.
The process of memorizing the bit of data by the memory cell is an example of the ingenuity of a memory device. Each memory device performs many other feats of engineering. The notion that information may be stored and extracted when desired involves the element of time. Memory device activities are timed to predictively perform according to a train of pulses. This train of pulses can be likened to the gestures of a conductor conducting a symphony. In the parlance of engineering, this train of pulses is known as a clock, and more specifically, the train of pulses is called a strobe when it is used to initiate the passage of data.
To start the process of memorizing the bit of data by the memory cell, a write signal is issued so that the bit of data may be written to the memory cell. The memory device, which houses the memory cell, delays the writing of the bit of data for a period of time until the write signal is validated by an appropriate transition in the strobe. Such a strategy may be fine for memory devices that are designed to work at low speeds, but it creates problems for the proper operation of future generations of memory devices.
Thus, what is needed are devices and methods to recognize the transition of the strobe at an appropriate time so as to enhance the speed of operations of future generations of memory devices, such as synchronous DRAMs (SDRAMs), and specifically, double-data-rate SDRAMs (DDR SDRAMs).